• Title, Summary, Keyword: Optimum coding method

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An Optimum Selection of Dual Coding Subfield Pattern for Plasma Displays

  • Kwak, Dong-Chan;Kim, Choon-Woo
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.730-733
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    • 2003
  • Dual coding technique is one of the popular techniques to reduce the dynamic false contours on PDP. Subfield pattern is a key factor affecting the performance of dual coding technique. In this paper, an optimum subfield selection method based on genetic algorithm is proposed. Two types of string structures are defined to account for all the possible configurations of the dual coding subfield patterns. Genetic operators are proposed for optimization of dual coding subfield pattern. Quantitative measures to describe degrees of dynamic false contours and checkerboard patterns are defined. Experimental results indicate that dual coding subfield pattern that is determined by proposed method reduces dynamic false contours and checkerboard patterns.

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A Study on Optimum Coding Method for Correlation Processing of Radio Astronomy (전파천문 상관처리를 위한 최적 코딩 방법에 관한 연구)

  • Shin, Jae-Sik;Oh, Se-Jin;Yeom, Jae-Hwan;Roh, Duk-Gyoo;Chung, Dong-Kyu;Oh, Chung-Sik;Hwang, Ju-Yeon;So, Yo-Hwan
    • Journal of the Institute of Convergence Signal Processing
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    • v.16 no.4
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    • pp.139-148
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    • 2015
  • In this paper, the optimum coding method is proposed by using open library in order to improve the performance of a software correlator developed for Korea-Japan Joint VLBI Correlator(KJJVC). The correlation system for VLBI observing system is generally implemented with hardware using ASIC or FPGA because the computational quantity is increased geometrically according to the participated observatory number. However, the software correlation system is recently constructed at a massive server such as a cluster using software according to the development of computing power. Since VLBI correlator implemented with hardware is able to conduct data processing with real-time or quasi real-time compared with mostly observational time, software correlation has to perform optimal data processing in coding work so as to have the same performance as that of the hardware. Therefore, in this paper, the experimental comparison was conducted by open-source based fftw library released in FFT processing stage, which is the most important part of the correlator system for performing optimum coding work in software development phase, such as general method using fftw library or methods using SSE(Streaming SIMD Extensions), shared memory, or OpenMP, and method using merged techniques listed above. Through the experimental results, the proposed optimum coding method for improving the performance of developed software correlator using fftw library, shared memory and OpenMP is effectively confirmed by reducing correlation time compared with conventional method.

A Study on the Power Allocation for AMC Scheme in OFDMA System (OFDMA 시스템에서 AMC를 위한 전력할당 방식에 관한 연구)

  • Kim, Dong-Cheol;Shin, Hyun-Joon;Hong, Een-Kee
    • Journal of Advanced Navigation Technology
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    • v.9 no.2
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    • pp.192-199
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    • 2005
  • Adaptive Modulation & Coding (AMC) is the method of varying the modulation and coding scheme for the changeable wireless channel environment. WiBro use AMC method because it has a very large variation caused by mobility interference and other cell interference. In this paper, we will compare and analysis the method of selecting the optimum MCS level for the efficiently use of mobile power consumption.

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Global Optimum Searching Technique of Multi-Modal Function Using DNA Coding Method (DNA 코딩을 이용한 multi-modal 함수의 최적점 탐색방법)

  • 백동화;강환일;김갑일;한승수
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.225-228
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    • 2001
  • DNA computing has been applied to the problem of getting an optimal solution since Adleman's experiment. DNA computing uses strings with various length and four-type bases that makes more useful for finding a global optimal solutions of the complex multi-modal problems. This paper presents DNA coding method for finding optimal solution of the multi-modal function and compares the efficiency of this method with the genetic algorithms (GA). GA searches effectively an optimal solution via the artificial evolution of individual group of binary string and DNA coding method uses a tool of calculation or Information store with DNA molecules and four-type bases denoted by the symbols of A(Ademine), C(Cytosine), G(Guanine) and T(Thymine). The same operators, selection, crossover, mutation, are applied to the both DNA coding algorithm and genetic algorithms. The results show that the DNA based algorithm performs better than GA.

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A Suboptimum Block Quantization in Image Transform Coding (영상 변환부호화에서의 준최적 블록양자화)

  • 심영석
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.22 no.6
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    • pp.41-45
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    • 1985
  • A suboptimum block quantization method is investigated for efficent transform coding. In our study the following method has appeared as suboptimum. At first, optimum bit allocation is done assuming the varances of the transform coefficients are known. Secndly, a varance estimation algorithm which results from the approximate equations governing the optimum vit alllocation is applied. The better performance of the proposed block quantization method has been confirmed by simulations based on varous pdf assumptions. the results indicate that the proposed method yields overall improvements of about 25% in NMSE for both the symmetric nonuniform and uniform quantizer at the coding rate of 1 bit/pel.

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A Quantizer Reconstruction Level Control Method for Block Artifact Reduction in DCT Image Coding (양자화 재생레벨 조정을 통한 DCT 영상 코오딩에서의 블록화 현상 감소 방법)

  • 김종훈;황찬식;심영석
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.28B no.5
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    • pp.318-326
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    • 1991
  • A Quantizer reconstruction level control method for block artifact reduction in DCT image coding is described. In our scheme, quantizer reconstruction level control is obtained by adding quantization level step size to the optimum quantization level in the direction of reducing the block artifact by minimizing the mean square error(MSE) and error difference(EDF) distribution in boundary without the other additional bits. In simulation results, although the performance in terms of signal to noise ratio is degraded by a little amount, mean square of error difference at block boundary and mean square error having relation block artifact is greatly reduced. Subjective image qualities are improved compared with other block artifact reduction method such as postprocessing by filtering and trasform coding by block overlapping. But the addition calculations of 1-dimensional DCT become to be more necessary to coding process for determining the reconstruction level.

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Optimized Channel Coding of Control Channels for Mobile Packet Communication

  • Song, Young-Joon
    • Journal of electromagnetic engineering and science
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    • v.3 no.1
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    • pp.50-56
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    • 2003
  • This paper proposes a coding scheme of control channel for mobile packet communication to maximize the minimum Hamming distance, which is based on shifting of basis vectors of Reed Muller code with optimized dynamic puncturing and/or(partial) sequence repetition. Since the maximum likelihood decoding can be performed using the extremely simple FHT(Fast Hadamard Transformation), it is suitable for real time optimum decoding of control channel information with very little complexity. We show applications of the proposed coding method to TFCI(Transport Format Combination Indicator) code in split and normal modes of 3GPP W-CDMA system. We also discuss how this method can reduce rate indication error over AWGN(Additive White Gaussian Noise) as well as fading channels when the proposed coding scheme is applied to 1xEV-DV system of $3^{rd}$TEX> generation partnership project 2(3GPP2) to indicate the data rate transmitted on the reverse traffic channel by a Mobile Station(MS).

Bit Allocation for Interframe Video Coding Systems

  • Kim, Wook-Joong;Kim, Seong-Dae;Kim, Jin-Woong
    • ETRI Journal
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    • v.24 no.4
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    • pp.280-289
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    • 2002
  • In this work, we present a novel approach to the bit allocation problem that aims to minimize overall distortion subject to a bit rate constraint. The optimal solution can be found by the Lagrangian method with dynamic programming. However, the optimal bit allocation for block-based interframe coding is practically unattainable because of the interframe dependency of macroblocks caused by motion compensation. To reduce the computational burden while maintaining a result close to the optimum, i.e., near optimum, we propose an alternative method. First, we present a partitioned form of the bit allocation problem: a "frame-level problem" and "one-frame macroblock-level problems." We show that the solution to this new form is also the solution to the conventional bit allocation problem. Further, we propose a bit allocation algorithm using a "two-phase optimization technique" with an interframe dependency model and a rate-distortion model.

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A Study on the performance evaluation with TCM and MTCM in the mobile radio environment (이동 무선 환경에서의 TCM 및 MTCM의 성능 비교 평가)

  • 김민호
    • Journal of the Korea Society of Computer and Information
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    • v.5 no.4
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    • pp.90-95
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    • 2000
  • In order to enhance the confidence in the mobile communication and improve the performance of the bit error, we have been using coding method. In the case of this, we have to add redundancy bits by using error correcting codes such as the block or convolutional codes. However, the result of redundancy bits causes to improve confidence. but to drop the efficiency in the bandwidth. We have studied coding method that we are able to get the good coding gain without any changes in the data transmission rates in the limited bandwidth. In this Paper, we design TCM(Trellis Coded Modulation) which was proposed by Ungerboeck and MTCM(Multiple TCM), with multiplicity(k=2), which was proposed by Divsalar, using the optimum encoder. As state number is varied in the optimum encoder, we compare the performance of the TCM and MTCM by using Monte Carlo simulation.

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A Study on Joint Source/Channel Coding for MPEG-4 Video Transmission (MPEG-4 비디오 전송을 위한 결합 소스/채널 부호화에 관한 연구)

  • Lee, Woon-Moon;Sohn, Won;Lee, Soo-In
    • Journal of Broadcast Engineering
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    • v.8 no.2
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    • pp.163-171
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    • 2003
  • In this paper, we develop an approach toward Joint Source-Channel Coding for MPEG-4(Moving picture Experts Group) based video coding In fixed and mobile reception environment. We have considered channel environment of AWGN and mobile reception. The source coder used MPEG-4 video. the channel coder used RCPC(Rate Compatible Punctured Convolution) and the modulation method used QPSK(Quadrature Phase Shift Keying) modulation. This study determined optimum Trade-off point between source bit rate and channel coding rate In variable channel states. We compared Joint Source/channel Coding method and general constant bit rate transmission. In this results, Joint Source/channel Coding was appeared better performance than constant bit rate transmission.